KnowledgeGrant untagged enum (Fact + Entity variants), ContentEntityRegistry resource, KnowledgeGranted event processing, ContradictionClaim struct with 600-tick window detection in observe_entity. Wires knowledge_grant field in dialogue line selection. Implements D-079, D-083. Closes Q-026. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>